Cold Start....

[Ender]

The average high so far this month at IAD is 37.3F, the average low, 22.4F...and the average temperature has been 29.9F.

That makes this December, to date, second only to 1989 which had an average high of 35.8F, low of 15.5F and average temp of 25.6F.

The next coldest, after this year, would be 2002 with 38.8F/21.6F and 30.2F. After that, and for the fourth, fifth and sixth spots on the list are Decembers 1968, 2000 and 2005 all of which were in the 31.3F - 31.8F range for their average temperature as of the 18th of December.

This is the 48th December in Dulles' climatological record. DCA, of course, has more...

So far this month Reagan's high has averaged 39.9F, their low is 27.8F and the average temp comes in at 33.9F. Those stats make this the fourth coldest start to December since 1944. The three colder Decembers were:

1958 with an average of 30.5F as of the 18th.

1989 at 30.7F.

1960 at 33.5F.

Assuming we don't end-up absurdly warm over the next 12 days this is going to rank as one of the coldest Decembers ever. I decided to look at those winters that included a December in which IAD averaged below 34.5F for the month. Those would be:

Winter Jan Feb Snow

1958 - 59 34.9 39.0 4.9" (DCA numbers, not included in ave's below)

1960 - 61 29.8 38.3 40.3" (DCA numbers, not included in ave's below)

Winter Jan Feb Snow

1962 - 63 28.4 29.3 6.3" (No Dec Records)

1963 - 64 33.4 30.9 44.6"

1968 - 69 29.4 32.2 23.5"

1969 - 70 23.9 32.7 30.2"

1976 - 77 21.0 34.8 10.6"

1988 - 89 36.3 35.2 9.9"

1989 - 90 40.8 42.2 29.2"

2000 - 01 32.1 38.5 12.9"

2002 - 03 28.4 30.3 50.2"

2003 - 04 28.0 34.8 17.4"

2005 - 06 41.8 36.0 13.8" (8.1" post Dec)

Those led to a January average of 31F and a February average of 34.6F or -.7F and -.2F from their respective long term means. If, however, we drop 1989 - 90 and 2005 - 06 then we end-up with a somewhat different picture with a January mean of 28.4F and February at 33.5F. Of course it's pretty hard to argue that '89 - '90 should be dropped...likewise it's hard to remove '05 - '06 for the same reason.

Enjoy!

(EDIT: Darn, I can't figure out how to make nice columns or a table.)

[Dr No]

26.5 is the record minimum Dec average at DCA from 1876 (which would be a -14.6 compared to the 71-00 avg.)

27.8 is the record minimum Dec average at IAD from 2000 (which is a -9.9)

To date (12/18):

DCA: 33.9 (-7.2)

IAD: 29.9 (-7.7)

Given that it looks like we will probably not pull a + anomaly the rest of the month, and that the dailies are likely to be much below normal, the IAD record may be achievble, especially if we can get some good radiational conditions post Dec 25. (In fact it would be likely if this was a leap year. December 1 )

The DCA one would likely not be broken in our lifetimes.

[Ender]

26.5 is the record minimum Dec average at DCA from 1876 (which would be a -14.6 compared to the 71-00 avg.)

Actually, not quite as there wasn't a DCA back then. Do you happen to know which station they're using for the pre 1945 data for Washington, DC?